Microcarrier culture is widely used within the cell culture area. In microcarrier culture the cells are either immobilised by attachment onto the surface of solid microcarriers or by attachment to or physical entrapment inside the internal structure of macroporous microcarriers. When using microcarrier culture a methodology is needed for retaining the carriers with cells in the culture vessel whilst harvesting the culture supernatant. One microcarrier-based process type is the continuous perfusion process, where culture supernatant is continuously harvested and new medium continuously added. In this process type the microcarriers are typically retained by means of a gravitational settler or an internal filter in the culture vessel. Another microcarrier-based process type is the semi-continuous process where batch wise harvesting of culture supernatant and addition of new medium is performed with regular intervals. In this process type the microcarriers are most easily retained by stopping the agitator of the culture vessel and thereby letting the carriers with cells sediment at the bottom of the vessel. When the cell-containing carriers have sedimented part of the culture supernatant is harvested and replaced with new medium, where after the agitator is started again. However, the lack of agitation during sedimentation endangers the cells of being subjected to lack of oxygen or nutrients. The present invention provides an improved method which improves the ability of the cells to withstand the conditions while they are sedimented at the bottom of the vessel and thus have a positive effect on the overall performance of the culture.